Studies involving the importance of internal locus of control on the rehabilitation process of any illness or disability tend to have numerous methodological problems. The subject groups selected and the indexes of outcome, as well as the manipulation of treatment, structures cause limited generalizability. Different studies contradict each other probably too frequently for strictly scientific purposes. This becomes obvious when looking at the various studies involving weight reduction and locus of control. However, in light of the great body of knowledge indicating a more than coincidental relationship between locus of control and outcome, it would be unwise to disregard it. Questionnaires exist that measure a person's internal locus of control, however, that extra inner essence of a person defies scientific exploration and measurement. The literature attests to the more than coincidental power that internally oriented people possess over their disabilities. And it seems that it is this power that can make the difference in a person's prognosis and quality of life. (ABL)